Cord-grip for pendant lights or other fixtures.



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WITNESS-E5- llNiTen STATES Patented February '7, 1905.

ATENT einen.

WALTER L. BRADSHAW, OF CAMBRIDGE, )lASSACHUSETTS.

CORD-GRIP FOR PENDANT LIGHTS OR OTHER FIXTURES.

SPECIFICATION forming part of Letters Patent No. 781,764, dated February'7, 1905.

Application filed May 27, 1904. Serial No. 210,000.

To (1f/7 /r/mnt it 'Ht/Ly concern:

Be it lcnown that I, TVALTER L. BRADsHAw, a citizen of the UnitedStates, and a resident of Cambridge, in the county of Middlesex andState of illassachusetts, have invented a new and useful improvement inPendant Electric Fixtures, of which the followingl is a full, clear, andexact description. reference being had to the accompanying drawings,forming a part of this specification, in explaining its nature.

My invention has reference to electric lixtures suspended by theconducting-cord, and

relates particularly to means Vfor preventing the stripping of the cord.from the terminal binding-posts by the weight of the fixture. Suchstripping is ordinarilyY prevented by lmotting this cord within therosette or socket, although in my copending application, Serial No.171,309, l have shown more etficient means for accomplishing thispurpose.

My present invention, like that o'f my aforesaid application, relates tomeans adapted to be attached to or formed a part of a rosette, alamp-lixture socket, or the like and is adapted to secure and engage thecord, thereby throwing the weight of the lamp-fixture upon the body ofthe rosette or upon the wire conducting-cord instead of upon thebindingposts. More particularly, however, my invention relates tolampsupporting means which are adapted to be connected toconducting-cords of varying sizes, such means being adapted topositively engage the conductingcord without any more careful or exactmanipulation than would be called for by an ordinary electrician orinspector in the performance of that work.

My invention involves the construction of a conductingcord clamp theelements of which are simple and the material cheap and of non-absorbentand non-resilient material, whereby the device is durable and does notlose its etliciency without a considerable lapse of time.

Having briefly set forth the object of my invention, l will now proceedto describe the same, reference being had to the accompanying drawings,in which- Figure i is a side elevation ot' my device,

the parts being assembled, but det-ached from the conducting-cord. Fig.2 is a similar view of the main element or body of my device, the samebeing a hollow member provided with a threaded extension vfor attachmenttoa rosette or lamp-socket. Fig. 23 is a side elevation of anotherelement of my device,which is adapted to be fitted within and to serveas a bushing in the threaded extension of the bodymember shown in Fig.2. Fig. Je is a side elevation of a loose element adapted to operate andto clamp a wire conductiiig-cord within the hollow member shown in Fig.L). Fig. 5 is a side elevation of a bushing through which the cordpasses in the top or cap portion of my device shown in Fig. l5. Fig. 6is a similar view of a cap or an adjusting member for controlling theposition of the clamping member shown in Fig. i. Fig. 7 is atop planview of the member shown in Fig. 3. Fig. S is a view in cross-sectionalelevation` showing my device in operative position and as attached to anordinary ceiling-rosette; and Fig. 9 is a view in elevation, partlyinsection, showing my deviceassembled and in operative position asattached to an ordinary Edison lamp-socket.

Referring to the various figures, the tubular piece or cup l, as shown,is provided with a threaded extension 3 forengagementwith a ceilingrosette or lamp-socl et piece. 'lhe piece 1 is also shown as having aneel( threaded at 3 for engagement with a second tubular piece or cap l.A. bushing or piece 5 (shown in detail in Fig. il) is adapted to litclosely within the neck or piece l, and a bushing or piece 6, providedwith a shoulder T, is adapted to lit within an opening 8 in the cap i toengage the cap at the Ishoulder, as shown in `Figs. S and 9. 'lhe piecesand (5 are shown as slightly rounded at their inside edges to preventabrasion of the cord on contact therewith. The piece l is shown asprovided with an internal strip of insulation 9.

Vithin the cap or casing l is a member l0 otI a size to permit it to befreely rolled or moved within the casing and to permit the cord to passbetween it and the wall of the casing when the device is in operation.This member is shown as a ball or marble; but so IOO it is adapted tooperate in the manner herein described and claimed its form is notmaterial.

The pieces 1 and 3 are preferably ot' brass or similar material, thepieces 5 and 6 of porcelain, and the marble of clay, although it isapparent that the material of the parts may be varied within widelimits.

The assemblage and operation of my device is as follows: The piece 6 islitted within the cap 4 and the cord passed through the opening therein.The piece 5 is iitted within the cup 1 and the cord passed through theopening in the piece 5. The cup l is then screwed into the ceilingrosette or socket and the terminals of the cord properly screwed to thebinding-post. The movable member or ball l0 is then pushed into the cupl and the cap 4 secured onto the cup. The cap 4 engages the shoulder ofthe piece 6, and the latter coacting with the member l0 kinks the cordat the point of contact, as shown in Figs. 8 and 9, in which positionthe cord is iirmly held from longitudinal movement through the device.The action of the several members in thus retaining the cord immovableis wedge-like. In Fig. 8, for instance, any pull upon the cord onlyserves to wedge the marble more tightly between the wall of the bodymember l and the opposing edge of the member 5, whereas in Fig. 9 anypull upon the fixture only serves to force the member l0 more tightlybetween the wall of the body member and the opposing edge of the member6. The cord and marble are maintained from direct contact with the bodyor cup member l by insulating-strip 9, which thus acts to prevent anyshort-circuiting through the iixture. It will be seen that any pull uponthe cord only tends to force the cord and marble more closely intocontact and prevent any yielding of the cord impossible. In the case ofbraided. cords the member 10 will lie over the line of the strands andwill cause the strands to lie side by side between it and the body-piece1 instead of lying over each other, in which position they might beinjured by pressure or strain. It is to be noted that the pressure ofthe clamping means upon the cord is not entirely transverse to the lineof strain, as is the case in certain other clamping devices, but thatthe cord is kinked and the pressure distributed along the bend. The cordbeing' jammed between the marble and the rounded inside edges of thepieces 5 and 6 may be said to be positively engaged by these elements,such engagement being thus distinguished from simple frictionalengagement such as might be produced by ordinary clamping-jaws.

It is obvious, furthermore, that my clamping device is not limited foruse with any particular size of cord, but by its very nature isadjustable to operatively engage cords of widely-varying sizes.Furthermore, owing to the nature of my clamping device and to the factthat any pull upon the cord only serves to force the marble into a moreefcientlyclamping position it is apparent that the cap 4 need not bescrewed down to the limit of its movement upon the piece 1, but willeffectivel y cause the clamping of the cord, even although onlypartlyscrewed down. Thisloose tit is of great practical importance, forthe reason that careless operation of electrical iiX- tures byinspectors and electricians often leaves the fixtures loosely assembled,and consequently, perhaps,inoperative and dangero us.

Although I have shown my device constructed in five pieces ofdefinite'shape, this precise construction is not essential, as it isobvious that certain of the pieces;t`or instance, the pieces 5 and maybe made integral with the pieces 1 Vand 4 or-may be omitted altogether,provided the pieces 1 and 4 are altered in form to answer the functionot' the absent parts.

Various other modifications in structure without departing from thespirit of my invention will be apparent.

Having thus fully described my invention, I claim and desire to secureby Letters Patent of the United States 1. A device for relieving thestrain on the terminals of electric wires, consisting' of a hollow shellor casing to embrace the conducting'- cord, means for attaching theshell or casing to a suitable support, and a grip adapted to roll in thecasing and to bind the conductingcord to said shell or casing with awedging action.

2. In a device of the character described, a hollow shell or casingprovided with means of attachment to the support for the electricwireterminals, such hollow casing having a passage therethrough for the wireconductingcord, a rolling member located within said hollow case, andmeans for controlling the position of the rolling member to cause thecord to be clamped in the casing with a wedging action.

3. In a device of the character described, a hollow shell or casingprovided with means of attachment to the support for the electric-wireterminals,- such hollow shell or casing having a passage therethroughfor the conductingcord, a marble or spherical member movab e within thecasing, and means for controlling the position of said spherical memberto cause the cord to be clamped within the casing.

4. In a device ot' the character described, a

hollow casing provided with means of attachment to the support for theelectric-wire terminals, said casing having a passage therethrough forthe conducting-cord, a movable member within said casing and meansadjustably engaging the casing and controlling the position of themovable member and to cause the cord to be clamped between the movablemember and the casing.

IOS

IIO

In a device ot' the character described, a shell or casing provided withmeans of attachment to the support for the electric-wire terminals, suchshell or casing having an openi ing tor the passage ot a cord, a movablememi ber loosely supported within said casing and means surrounding thecord to control the position ot' the movable member to cause the casingto be clamped to the cord.

In a device of the character described, a shell or casing provided withmeans of attachl ment to the support of the electric-wire terminals,said shell or casing having' an opening tor the passage of theconducting-cord for the wires, a movable member loosely supported iwithin said casing and means adjnstably engaging the casing to limit theplay and to control the position of the movable member t0 cause thecasing to be clamped to the cord.

T. In a device ot' the character described, a l casing provided withmeans of attachment to I the support of the elect1ic\vire terminals,said casing having a passage therethrough for the conducting-cord forthe wires, a rolling member within said casing and means for controllingthe position ot' said member to cause the alinement ot' the cord withinthe casing to be hinked or interrupted and the cord to be clamped withinthe casing b v a wedge action ot' said member.

8. In a device oi the character described, a casing provided with meanset attachment to the support for the electric-wire terminals, saidcasing having opposing openings therein l for the condueting-cord, arolling member within said casing and means for controlling the positionof said member to cause the alinement of the cord between said openingsto be liinlied or interrupted, and the cord clamped within the casingwhereby the whole device is tirmly attached to the cord.

t). A device for relieving the strain on the terminals of electricwires, consisting of a hollovv shell or casing to embrace aconductingcord, said shell or casing having au interior insulatinglstrip or hoop, means for attaching said casing to a suitable support anda grip loosely supported and freely movable within the casing and meansadapted to cause the grip to bind the conducting-cord against theinsulation ot' the casing with a wedging action, substantially asdescribed.

lVALTIC R L. BRA DSI l A W. ln presence ot' J. M. DoLAN, M. V. FOLEY.

